Emergency Medical Services (EMS) Systems
Last Updated: March 2022
Emergency Medical Services (EMS) include services that are provided outside of the hospital setting that include transport to care facilities or to patients with illnesses and injuries that the patient believes constitute a medical emergency. Many states track the number of naloxone administrations as a proxy of opioid overdose treatment by EMS because this data is often routinely collected by EMS and coincides with strategies to reduce opioid overdose mortality (e.g., medication administered). Some jurisdictions also monitor patient’s response to naloxone administration (e.g., improvement in respiratory rate and Glasgow Coma Scale score) to estimate the lives saved by administering naloxone to patient’s experiencing an opioid overdose (See the New Hampshire Drug Monitoring Initiative reports). Assessment of medication administered (e.g., naloxone) in combination with improved response to medication can also help to reduce the number of false positives identified through this data source (e.g., naloxone administered to a person not experiencing an overdose).
A strength of EMS data is that it may include people who are treated, but refuse transport to the emergency department (i.e., will not be captured in emergency department data). Because EMS responders have limited information when providing treatment and EMS response protocols for suspected overdoses vary across jurisdictions, misclassification of EMS transports may occur (e.g., patient given naloxone who was not experiencing an opioid overdose or patient experiencing an opioid overdose were not given naloxone). To reduce misclassification, some jurisdictions have designed more complex definitions to identify EMS transports related to opioid overdoses (See Rhode Island).
EMS Systems: NEMSIS
National Emergency Medical Services Information System (NEMSIS)
The Office of EMS in the National Highway Traffic Safety Administration (NHTSA) manages the National Emergency Medical Services Information System (NEMSIS), which aims to collect and store standardized data from EMS agencies across the United States. NEMSIS is a universal standard for how patient care information resulting from an emergency 911 call for assistance is collected.
EMS Systems: Biospatial
BioSpatial is a web-based data dashboard used to display Emergency Medical Services Information System (EMSIS) data. General information can be gathered here: https://www.biospatial.io/state-ems-agencies/.
Michigan is a state that uses BioSpatial dashboards, Michigan is linked HERE.
EMS Systems: Nonfatal Opioid Overdose Case Definition
CSTE, in conjunction with national EMS partners conducted a series of field tests and validations to determine standard queries for determining nonfatal opioid-related overdoses. As noted in the table above, some data elements are required for reporting to the National EMS Information System (NEMSIS). Further, some elements are coded, or have a drop-down selection menu associated when EMS personnel select these options. The guidance recommends jurisdiction utilize a combination of six coded elements and selected free text elements. The coded data elements are listed below:
- Provider’s Primary Impression
- Provider’s Secondary Impression
- Primary Symptom
- Other Associated Symptoms
- Medication Administered
- Response to Medication Administered
For the free-text elements, CSTE recommends using selected terms from the narrative field, though this recommendation depends on each jurisdiction’s access to that field, available resources for any necessary analysis, and local restrictions regarding use of the narrative. In the CSTE field test project, specific terms were recommended and revised, and these terms yielded improvements without sophisticated natural language processing methods.
Jurisdictions may already have overdose case definitions in place for identifying probable opioid overdoses. Most of these definitions utilize key EMS data elements listed in the table below:
| Useful NEMSIS Data Elements for Overdose Surveillance | |||
|---|---|---|---|
| Data Source | NEMSIS v3 Variable | NEMSIS v3 Variable Definition | NEMSIS v3 Variable Response Options |
| Patient Care Report Narrative | eNarrative.01 – Patient Care Report Narrative | The narrative of the patient care report (PCR). | State, E, 0:1 String values 1-10000 characters |
| Medication administered by EMS | eMedications.03 – Medication Given | The medication given to the patient |
National, State, R, 1:1
|
| Response to medication | eMedications.07 – Medication Given | The patient’s response to the medication |
National, State, R, 1:1
|
| Primary impression (including ICD-10-CM codes) | eSituation.11 – Provider’s Primary Impression | The EMS personnel’s impression of the patient’s primary problem or most significant condition which led to the management given to the patient (treatments, medications, or procedures). | National, State, R, 1:1 ICD-10-CM codes: (R[0-6][0-9](\.[0-9]{1,4})?|(R73\.9)|(R99))|([A-QSTZ][0-9][0-9A-Z])((\.[0-9A-Z]{1,4})?) |
| Secondary impression | eSituation.12 – Provider’s Secondary Impressions | The EMS personnel’s impression of the patient’s secondary problem or most significant condition which led to the management given to the patient (treatments, medications, or procedures). | National, State, R, 1:M String values based on ICD-10-CM codes, 1-255 characters |
| Primary Symptom | eSituation.09 – Primary Symptom | The primary sign and symptom present in the patient or observed by EMS personnel (Including ICD-10-CM codes) | National, State, R, 1:1 ICD-10-CM codes: (R[0-6][0-9](\.[0-9]{1,4})?|(R73\.9)|(R99))|([A-QSTZ][0-9][0-9A-Z])((\.[0-9A-Z]{1,4})?) |
| Other Associated Symptoms | eSituation.10- Other Associated Symptoms | Other symptoms identified by the patient or observed by EMS personnel | National, State, R, 1:M ICD-10-CM codes: (R[0-6][0-9](\.[0-9]{1,4})?|(R73\.9)|(R99))|([A-QSTZ][0-9][0-9A-Z])((\.[0-9A-Z]{1,4})?) |
| NOTE: This list is meant to be a tool to highlight NEMSIS data elements that may be useful for opioid overdose surveillance. It is not exhaustive in nature and should not replace any standing jurisdictional guidance. |
| Data Element Key | |
|---|---|
| National and State Element Indicator | NEMSIS v3 Variable Response Options |
| National = Yes, is an indication that the data element is required to be collected at the local EMS agency level and submitted to the state State = Yes, is an indication that the data element is recommended to be collected at the “State” level. |
M = mandatory data field, does not allow NOT values R = must be completed and allows NOT values [7701001 – Not Applicable; 7701003 – Not Recorded] E = recommended field 0:1 = element is not required and can occur only once 1:1 = element is required and can occur only once 1:M = element is required and can repeat multiple times |
| Source: NEMSIS Data Dictionary (DEM/EMS Dictionary v3.4.0) |
| NOTE: CSTE Nonfatal Opioid Overdose Standardized Surveillance Case Definition will be updated with a standard guidance for determining nonfatal opioid-involved cases from EMS data. |
| NOTE: Recommendations for the Use of EMS Data to Identify Nonfatal Opioid Overdose |
Toolkit Resources
Get more insights by using our toolkit resources.
Go to Resources
Glossary
Learn the definition of the key words being used.
Go to Glossary
Thanks
Thank you, to all of our contributors.
View our contributors
the public’s health.
Contact Us
Have any questions or recommendations, you can contact us at overdose@cste.org